Add formula for cabal-install

Cabal is a system for building and packaging Haskell libraries and
programs. It defines a common interface for package authors and
distributors to easily build their applications in a portable way.

cabal-install is the command line interface to Cabal and hackage. This
is the package that provides the 'cabal' command line program. To make
the process easier the cabal-install tarball contains a bootstrap.sh
script which downloads and installs all three dependencies.

	http://www.haskell.org/cabal/

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/cabal-install.rb

@@ -0,0 +1,14 @@
+require 'formula'
+
+class CabalInstall <Formula
+  url 'http://www.haskell.org/cabal/release/cabal-install-0.8.2/cabal-install-0.8.2.tar.gz'
+  homepage 'http://www.haskell.org/cabal/'
+  md5 '4abd0933dff361ff69ee9288a211e4e1'
+
+  depends_on 'ghc'
+
+  def install
+    ENV['PREFIX'] = prefix
+    system "sh", "./bootstrap.sh", "--user"
+  end
+end